It’s a Step Up for the users of Samsung Galaxy S3 GT I9300 smartphone as an all new Official build of Jellybean 4.2.1 firmware has arrived and in the due course of this article we will be checking out the same on how to apply this. Please note that this is the Official firmware which got leaked from Samsung and is not a custom ROM firmware. Applying this update won’t hamper the process of firmware update. There were couple of firmwares which was having the Jellybean build but this built is one of the most stable builds along with which it’s also having many new features which we have mentioned below;

Before we proceed to the detailed tutorial on how to apply this firmware update, let’s check out on what are the detailed change log of this new build of Jellybean 4.2.1 firmware which is dubbed as XXUFMB3.

Change log of Jellybean 4.2.1 Firmware:

Based on JOP40D Jellybean 4.2.1 Firmware,

Bugs are fixed in Ripple Effect on Lock Screen,

New Lock Screen and Widget Support as its Jellybean 4.2.1,

Daydream (Settings>Display)

New Additions in Notification Center

Notifications are more actionable

Voice Command (Allows you to control various parts of the phone using voice commands)

Quick Pre Requisites:

All the data in your Samsung Galaxy S3 i9300 smartphone should be backed up manually and not with KIES or ROM Manager as it may brick the device completely. With the help of below mentioned steps, you can easily create a backup.

From the path “Settings > Applications > Development > USB debugging”, enable the USB Debugging and also make sure that your device is left with the minimum of 40% or the device will get turned off in the middle of customizing process. Ensure that your device is not rooted.

Disclaimer: Though we don’t like to give any disclaimers, the only thing we would like to tell you is that please follow all the instructions mentioned in this article or else there is a risk of bricking your device for which we should not be held responsible.

Let’s proceed to the next step where we have summed up a detailed guide on how to apply this firmware update.

Now, turn Off your phone so that it can be entered in the Download Mode. Download mode in Galaxy S3 GT I9300 can be entered by pressing Volume down Key, Center button, and holding both simultaneously press the Power Button after which you will get to see a green robot indicating that the device has entered in the download mode.

Connect your Galaxy S3 to the computer with the help of original USB cable and then you will see that the ID : COM section will turn Yellow indicating that all the drivers have been installed successfully.

Click on “PDA” option to select “” and click on “Start” to start the process of firmware update. Once the firmware is updated successfully, you will see that the firmware application process will be commenced.

Once the firmware is updated successfully, the device will be rebooted. Till you see the country selection option, don’t pull out the USB cable.

Once you see the home screen, disconnect the device and head over to the path “Settings > About Phone” where you will be able to see the firmware version as Jellybean 4.1.2 firmware XXUFMB3 Jellybean 4.2.1.

Tip: Just in a rare case if the device doesn’t boot up or gets into the continuous Boot loop mode, you need to reinsert the battery and boot the device normally. Or else you need to re-apply the update by following the steps above.

So, there you go, you have now successfully applied the update of Jellybean 4.2.1 firmware. Do let us know if you come across with any issues as we will try our level best to sort out the same.

yeah this 4.2.1 updates cool..just it middle east stock..has to factory reset then its ok..but how to disable the jews calendar???? thanx mr.pradeep nela..email me if there is 4.2.2 update..or any file that s4 has can use for s3 without rooted

First of all I think there’s a mistake in the article: “All the data in your Samsung Galaxy S3 i9305 smartphone ” – shouldn’t it be I9300?
Now the question – will this set the Device Status to Modified (increase custom binary count)?

This firmware is buggy. Touch becomes slow. Sometimes not working while we have to call to another by scrolling left to right. At that time we have to close phone calling menu then reopen it and then working. Its bug. And another bug is screen clearity at upparside becomes dark.

I can not open messages either. And it does NOT help to clear the cache!
But worst of all, I have tried to roll-back to XXELLA firmware, but the phone will not start up. It just keep showing the Samsung logo.

I have probably found the cause to why many people (including myself) cannot open messages after applying this firmware.
The XXUFMB3 firmware does only have English language and some I believe is Arabic. Therefore, I believe that maybe that can be the reason why messages does not work since my phone configured to Danish.
After I went in recovery mode and “Wipe Data/Factory Reset”, I could install XXEMB5 without any problems.

This is the first official firmware I have seen that has not all languages included.
Do you have an ETA when there will be an official 4.2.1 or 4.2.2 firmware with all languages included?

i am nithin, i am a huge fan of android advices, i am using galaxy note 2, my previous smartphone was galaxy s2 and did all my updates frm ur website, all the official firmwares like ics, jellybean etc.
now i am using note2 and i cannot find any official updates released by this website, r u not dealing with note 2 ???